When a giant crack is blocking your view of the road, it's obvious your windshield needs replacement. However, there are many more subtle signs that a tiny crack or edge damage has ruined the seal on your windshield. Determine when it's time to get the windshield inspected, and potentially replaced or at least resealed, by watching out for these five signs of water leaks.

Moldy Odors

While you might think you'd notice wet carpet or upholstery first after your windshield springs a leak, these absorbent materials often wick up the moisture before you feel anything. The trapped water causes mold and mildew to flourish out of site. You'll definitely smell the musty, unpleasant moldy smell though. Of course, moldy odors can come from any leak, not just windshield seal problems. Visible mold growth limited to the front seat and floors is a stronger indicator the water is coming in through the windshield instead of a poorly sealed window or antenna hole.

Ruined Computers

Any car made in the last decade features at least one important on-board computer for calculating fuel to air ratios, emissions, and other data. Many cars won't start if the powertrain control module (PCM) is damaged, and this device is often located where a leaky windshield causes it to short out. A mechanic or windshield replacement technician can test the PCM to see if it's the cause of a car that refuses to start, but only disassembling the part allows them to discover if it was damaged by water or something else.

PCMs that quit working shortly after replacement are likely getting shorted out by a windshield moisture problem. Water flowing into the dashboard and under the hood can also damage other sensors and sensitive computer parts, causing false Check Engine lights and strange error codes during a data reading.

Interior Rust Spots

Rust requires moisture to start and spread, so you shouldn't see dark red spots forming on the interior of a well-maintained car. Check for rust in likely spots such as

  • The floorboard of the front driver's and passenger's seats, underneath the carpeting and pad
  • The inside of the door panels, especially along the bottom if it's a windshield leak and not a window problem
  • The main column of the dashboard, which is covered by the interior panels and requires the help of a body technician to inspect.

One pinhole of rust can weaken the entire frame's integrity if you don't catch it in time. It's best to use the other signs and symptoms of a leaky windshield to catch a problem instead of waiting until corrosion develops. A quick windshield replacement after a leak is discovered still costs less than full bodywork due to extensive rust.

Mineral Stains

Keep an eye on the dashboard and windshield if you suspect a leak and look for white spots or streaks. Minerals in the water get left behind as the moisture evaporates, leaving only a faint white residue. Streaks on the inside of the glass are difficult to clean off and show that water's penetrating the seal.

Fogged Windows

Finally, watch what happens inside the car when it sits parked in the sun after a rain storm. Do you notice any fog developing on the windows? There's definitely water trapped inside the car, although interior dampness doesn't tell you where the water is coming from exactly. You'll still need to run a water hose over the windshield and watch from the inside for droplets to figure out if the seal is the culprit.

Even with all these signs and tests, it's still hard to pinpoint the exact leak with such a large seal around the windshield glass. Let the professionals test each inch for pressure to ensure the seal is properly seated after repairs too. Check out sites like http://www.mrgoglass.com for more info.